The present invention relates to high voltage winding lead and terminal structure. More particularly, the present invention relates to a high voltage winding lead and terminal structure which substantially decreases the probability of corona breakdown between the winding and the electrical connection to the inner turns of the winding.
In high voltage windings used in television receivers and other applications to generate high voltages, a potential difference of several thousand volts is often present between the outer turns and inner turns, or in other words, between opposite ends of the winding. In many applications, this potential difference may be 10,000 to 30,000 volts. For example, in generating the approximately 30,000 volts required for the anode of the typical cathode ray tube in a television receiver, a high voltage winding is used on the horizontal output or fly back transformer. In the slot wound transformer as disclosed herein, a large potential difference would exist between the inner and outer turns of the windings of each slot. For example, as disclosed in a preferred embodiment which utilizes four slot windings, the potential difference across each of these windings would be approximately 8 to 10 kilovolts (hereinafter sometimes designated kv.).
In slot wound transformers the possible corona breakdown problem exists with respect to making a connection to the first of the high voltage slot windings and also with respect to making crossover connections between the slot wound windings. Certain types of slot wound transformers have been used in the past. For example, U.S. Pat. No. 3,573,694 -- Eugene K. Von Fange et al, assigned to the assignee herein, discloses a slot wound transformer provided with progressively increasing diameters for the high voltage slots. Prior to the teachings of that patent, slits at right angles to the windings were provided in the partition members between the slot windings in order to enable the crossover connection between windings. U.S. Pat. No. 3,573,694 discloses the concept of slanting the slits at an acute angle to the central axis of the coil form in order to increase the electrical path length between the windings. However, these prior teachings require that the fine wire making up the winding be drawn down adjacent a number of layers of the winding thereby increasing the potential for corona discharge between the fine crossover wire and the turns of fine wire of the winding. For a given number of turns in a winding, the problem of corona breakdown becomes more acute as the number of component coils in the winding is reduced and replaced with fewer coils of greater height. This is because corona breakdown propensity is a direct function of the potential difference from the start to finish of each coil. solves these problems by means of novel structure which effectively increases the diameter of the electrical conductor which traverses the distance between the start and finish turns of each coil.